Toothbrushes are generally made in a method in which nylon bristled stock is anchored to a plastic toothbrush head via a metal staple. This requires a minimum head thickness of around 5 millimeters in order to reduce the possibility of plastic breakage during the stapling process given the tuft densities of most standard brushes. Furthermore, the toothbrush head and handle is generally molded in one step and it is a solid plastic part. This does not lend itself to placement of a light source in the toothbrush head.
In another well known process called in-mold tufting (IMT), nylon bristles are gathered and placed in an injection mold. Plastic is then injected around the bristles forming the toothbrush head and handle. The head must be large enough that plastic can flow over and around the “fused balls of nylon” commonly seen in these type of processes. The plastic over the fused balls retains the tuft in the brush during normal use. Once again there are generally no allowances made for insertion of a light source.
In each of these methods, incorporating a light source requires a post-processing step, such that the head must be made to accommodate a light source or the transmission of light from a source outside of the head. This post-processing requires time and resources, and often increases the cost to an unacceptable level. Or as an alternative, it requires making the head at a greater thickness (allowing for creation of a hollow section) increasing discomfort for the user while decreasing the user's ease of maneuverability. Accordingly, there is a need, therefore, for a practical, cost-efficient method of forming a light-emitting oral care implement, such as a toothbrush, that has an acceptable thickness and that is comfortable to the user.
Such need is met using a method of making an oral care implement or toothbrush where, for example, a head plate and handle are molded separately. The head plate is filled with cleaning elements such as nylon and the nylon is melted to an extremely thin “mat”. Afterwards, this relatively thin head plate is ultrasonically welded to the handle. In this method there is an open cavity in the toothbrush head, or the toothbrush head is effectively hollow, allowing the opportunity to place light emitting elements or other items in the toothbrush head that may provide a therapeutic or cosmetic benefit. Included could be alarms or sonic other device that signal proper or improper brushing techniques, proper amount of brushing time, etc.